Protected area downgrading, downsizing and degazettement (PADDD) is a global phenomenon that has not received formal attention in Reducing Emissions from Deforestation and Forest Degradation (REDD+) policies designed to reduce forest carbon emissions and conserve biodiversity. Here, we examine how PADDD affects deforestation and forest carbon emissions. We documented 174 enacted and 8 proposed PADDD events affecting more than 48,000 km2 in three REDD+ priority countries: Democratic Republic of the Congo, Malaysia, and Peru. Where sufficient data were available, we estimated deforestation rates and the quantity and economic value of forest carbon already lost and at risk in three land tenure classes: PADDDed, protected, and never-protected. PADDDed forests experienced deforestation and forest carbon emissions greatly exceeding rates in protected areas and slightly exceeding rates in never-protected forests. PADDD represents business-as-usual for protected areas, posing substantial risk to forests and forest carbon stocks. REDD+ policies have substantive implications for protected area biodiversity and forest carbon emissions; the Warsaw Framework for REDD+ provides new, but insufficient, guidance for nations to address these issues.